1. Field of the Invention
The present invention relates to monoclonal antibodies against human immunoglobulin E (IgE), a mixture thereof, hybridomas producing the monoclonal antibodies, and immunoassays of human IgE employing the monoclonal antibodies. The monoclonal antibodies according to the present invention are useful for clinical diagnostic agents to determine human IgE.
2. Prior Art
IgE is an immunoglobulin identified in 1966 by Ishizaka et al and it binds to mast cell or basophil surface via Fc receptor and reacts with allergens, thereby causing an immediate-type allergy. An IgE level in blood is quite low as compared with other immunoglobulins, but it significantly increases in the cases of allergic diseases, hepatic failure and parasitic infections, thus being characterized by the broad range of the levels in blood. Accordingly, to determine IgE level in blood is useful for diagnosis of allergic diseases or parasitic infections. The methods commonly used for this purpose include radioimmunoassay (RIA) and enzyme immunoassay (EIA) methods.
Monoclonal antibodies specifically reacting with human IgE have already been reported by Ichimori et al (Hybridoma, 4, 47 (1985)) and a method for determining human IgE in blood employing human IgE-specific monoclonal antibodies has also been reported by J. Grassi et al (J. Allergy. Clin. Immunol., 77, 808 (1986)). However, when such a conventional method employing monoclonal antibodies is used to determine human blood IgE, problems such as limited range of the determination and complicated determination procedure are experienced. Further, since the calibration curve is not always linear, the sensitivity is varied depending on the range of the concentrations to be determined and all the concentrations so determined are not reliable. The conventional methods also require special devices. All these problems and inconvenience can not be eliminated at a stretch by the conventional methods.